Circular knitting machine

ABSTRACT

A circular knitting machine of the type providing a reinforcement of knit tubular fabric for flexible hose, having a needle cylinder provided with a series of like pairs of spaced slots containing individual latch needles therein wherein the latch needles function in cooperating pairs. The machine functions the pair of needles in each pair of slots in unison with their hooks commonly disposed during such operation, to knit a wale of single spread stitches upon each pair of needles, the needle cylinder having a forecut common to each pair of spaced slots. A long shanked needle and a short shanked needle comprise each pair thereof with the short needles operated by a first set of cams and with the long needles operated by a second and similar set of cams, the cam sets being spaced and being angularly displaced a number of degrees equal to the number of degrees in the angular spacing between the needle slots of each pair thereof.

United States Patent [191 Greczin et al.

[ Mar. 18, 1975 CIRCULAR KNITTING MACHINE [76] Inventors: John Greczin, 7312 School Ln.,

Melrose Park, Pa. 19126; Roy D. Faigenbaum, deceased, late of 4072 Mountain Rd., Melrose Park, Pa. by Sylvia Faigenbaum, executrix [22] Filed: Dec. 27, 1972 [21] Appl. No.: 316,878

Primary E.\'aminer-Wm. Carter Reynolds Attorney, Agent, or F irm-Weiser, Stapler & Spivak [5 7] ABSTRACT A circular knitting machine of the type providing a reinforcement of knit tubular fabric for flexible hose, having a needle cylinder provided with a series of like pairs of spaced slots containing individual latch needles therein wherein the latch needles function in c0- operating pairs. The machine functions the pair of needles in each pair of slots in unison with their hooks commonly disposed during such operation, to knit a wale of single spread stitches upon each pair of needles, the needle cylinder having a forecut common to each pair of spaced slots. A long shanked needle and a short shanked needle comprise each pair thereof with the short needles operated by a first set of cams and with the long needles operated by a second and similar set of cams, the cam sets being spaced and being angularly displaced a number of degrees equal to the number of degrees in the angular spacing between the needle slots of each pair thereof.

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54 PRIOR ART PRIOR ART 4 1 CIRCULAR KNITTING MACHINE BACKGROUND OF THE INVENTION The present invention relates generally to the art of knitting and more particularly is directed to circular knitting machines of relatively small diameters of the type used to knit a reinforcement of tubular fabric in place upon and for flexible hose and the like as it passes through the machine.

In the production of such tubular knit fabrics, which serve as reinforcement for and which are formed in place upon the outer side of flexible hose (which may be of rubber, of plastic or of other material), it is desirable that the fabric should have a maximum of effectiveness as a reinforcement for the hose and in so doing should provide a maximum of burst strength in the finished hose. It is known that the size and disposition of the stitches in the knit fabric have a bearing upon its effectiveness as a reinforcement in the hose and for maximum effectiveness it is known that there should be a generally uniform distribution of the yarn components of the stitch formation in such manner that the coursewise width of the stitches in the needle wales should be generally equal to the distance between such wales and that the Wale-wise length of the stitches should be such that they are of generally hollow square formation.

The attainment of fabric having the above set forth desirable stitch formation is the object of the U.S. Pat. to Dauphinais, No. 2,752,952, wherein the means to do so comprise a machine having a modified form of needle cylinder and three modified forms of latch needles for use therein. The needle cylinder is modified by having wider than normal slots formed therein, the slots being approximately three times normal width. The patentee provides for use in such widened slots, a special latch needle which is much wider than a conventional latch needle, and, as an alternate construction,

three conventional latch needles of uniform length which have been connected together. A second alternate construction showing three unconnected conventional latch needles of uniform length is also set forth. The extra width latch needle (as wide as three conventional needles) is objectionable because it is of special construction, is more expensive than conventional needles, and has never been available in the manner in which conventional latch needles are available to the trade. Additionally, the machine containing such needles must be operated at much lower speeds because the shock of the opening and closing pivotal movements of the wide and heavy latch would result in damage thereto and to the stitches, which would require down time for needle replacement. Due to the heavy construction of such a needle, inertia and shock problems are developed in the machine. The three connected conventional needles in each of the wide slots is objectionable because this would require a cam track of excessive width within which the three joined butts would be relatively loose so that normal high speed knitting with a loosely fitting cam track could only result in excessive down time of the machine and costly needle replacement. The three unconnected needles in each of the wide slots is also objectionable because all three of the needles could not possibly be on top of the raise cam or be on bottom ofthc stitch cam at the same time, thus there would be latch clearing as well as stitch drawing of the single stitches at different times by each of the three needles. The first needle would have cleared the stitch and taken yarn on its downward movement before the third needle would have risen high enough to clear the very same stitch so that the yarns would frequently be broken as a result of being clamped, pinched and caught between the needles and their latches. This construction would necessitate frequent needle replacement because of the non-uniform clamping action of the stitches on the latches and the needle hooks during the non-uniform cast off and stitch drawing movements of the three needles.

SUMMARY OF THE lNVENTlON The attainment of fabric having the above set forth desirable stitch formation is also the object of the U.S. Pat. to Greczin, No. 3,543,280, wherein the means to do so comprises a needle stem with six equally spaced needle slots and eight equally spaced needle slots.

It is the principal object of the present invention to attain the fabric having the above set forth desirable stitch formation by means which comprise an improvement over the means disclosed in the said Dauphinais patent and the said Greczin patent and to provide a machine using conventional needles and operating at the normal high speeds to produce the fabric.

It is an object of the present invention to provide circular knitting machines with needle cylinders having a series of uniformly spaced pairs of slots within each pair of which conventional latch needles are individually lengthwise movable to and between stitch forming and latch clearing positions, and with means to so move the pair of needles in each pair of slots in unison.

It is also an object of the present invention to provide circular knitting machines with needle cylinders having a series of uniformly spaced pairs of slots with a short needle length-wise movable in one of the slots and with a long needle lenthwise movable in the other of the slots of each pair thereof, and with a pair of needle operating cam sets individually related to said long and said short needles to move each pair thereof in unison.

It is a further object of the present invention to provide a novel circular knitting machine that is inexpensive in manufacture, simple in design and trouble free when in use.

With the above and other objects in view which will become apparent from the following detailed description of a preferred embodiment of the invention as shown in the accompanying drawings, the present invention resides in the novel elements of construction, combination of parts and method of operation of the fabric forming means illustrated in the drawings and as hereinafter particularly pointed out in the claims.

BRIEF DESCRIPTION OF THE DRAWlNGS FIG. 1 is a vertical sectional view through a portion of a four feed circular knitting machine of the type adapted to produce reinforcement of knit tubular fabric upon flexible hose passing upwardly through its cylinder, and partially broken away to expose internal construction details.

FIG. 2 is a plan view of the lower needle cylinder and the upper needle stem of the machine of the present invention showing the paired disposition of the slots therein and showing the forecuts common to each pair of slots in the stem.

FIG. 3 is an enlarged, partial, perspective view of a portion of the needle stern showing a pair of needle slots and the forecut common thereto.

FIG. 4 is a top plan view of the needle stem of FIG. 3.

FIG. 5 is a cross-sectional view of the needle stem of FIG. 4 taken along Line 5-5 and looking in the direction of the arrows.

FIG. 6 is a partial perspective view of a portion of a prior art type of needle stem.

FIG. 7 is a schematic layout of the angularly displaced upper and lower needle operating cam sets of the four feeds of the machine of the present invention and the disposition therewith of the pairs of long and short needles.

FIG. 8 is an enlarged fragmentary elevational view of a section of hose provided with a covering of knit tubular fabrics, the stitches of which are of the type and size made in accordance with and by the apparatus of the present invention.

FIG. 9 is a detail view showing the hook portions of a pair of common level spaced latch needles having a single spread stitch of yarn in latch clearing position on their shanks, with yarn in their hooks preparatory to drawing a stitch thereof.

FIG. 10 is a detail view similar to FIG. 9 showing the common level spaced latch needles with a newly drawn single spread stitch in their hooks.

FIG. 11 is a detail view of a portion of the prior art type of needle stern of FIG. 6 showing the impossibility of forming wide stitches.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to the particular structure of our invention selected for illustration in the drawings, and are not intended to define or limit the scope of the invention.

The knitting machine of the present invention, as shown in FIG. 1, is provided with a stationary lower hollow needle cylinder 10 and with a stationary upper hollow needle stem 12 positioned above the lower cylinder. The cylinder 10 and the stem 12 are secured in position upon the upper end portion of a central stationary hollow cylindrical post 14 of the machine by means of suitable screws 16 and 18, respectively. The cylinder 10 is provided with a series, here shown as six in number by way of example only, of equally spaced pairs of spaced radial lower slots 20 and 22, FIG. 2, extending vertically through the walls thereof with the pairs of lower slots angularly spaced a greater number of degrees B than the angular spacing A between the slots of each pair thereof. The manner of determining the angular spacing between the lower slots 20 and 22 of each pair thereof, which is indicated at A in FIG. 2, will be set forth herinafter. Interiorly grooved needle bars 24 are individually placed in the lower slots 20 and 22 of the cylinder 10 and are retained therein by a clamping ring 25 extending peripherally about the upper portion of the cylinder. The needle stem 12 is provided with a like series of six equally spaced pairs of vertically extending, spaced radial needle upper slots 26 and 28 which are aligned with the needle grooves in the bars 24 and which have the same angular spacing as the lower slots 20 and 22 of the cylinder 10. The spacing 60 between the adjacent needle slots 26, 28 is fabricated to the desired width, for example the width of an additional needle slot, to permit the knitting of a wide wale tubular fabric 11. The stitches thus produced are wider than the width of the two needles 32, 34 but only two needles are required. The upper edge portion of the stem 12 is undercut along its periphery, as at 30, between each pair of upper slots 26 and 28. The undercut portion 30 extends a short distance laterally beyond the dots 26, 28 outwardly of their non-adjacent sides to provide a forecut common to each such pair of slots and within which the stitches formed by needles disposed in each such pair of slots may extend. The undercut portion 30 extends downwardly within the upper edge portion of the needle stem 12 a distance at least sufficient to correspond to the length of travel of the needles 32, 34 between their latch clearing and cast off position and within which the stitches which are formed by the needles which are disposed in the upper slots may extend. As best seen in FIGS. 2, 3 and 4, the undercut portion 30 extends inwardly from the outer periphery of the needle stem 12 to a depth at least equal to the depth of the base of the upper slots 26, 28. It will be noted (FIG. 3) that the upper slots 26, 28 upwardly terminate at the undercut portion 30 and below the upper edge portion of the needle stem 12.

Conventional latch needles are individually placed in each of the six pairs of needle upper slots 26 and 28 of the stem 12 and in corresponding aligned needle grooves in the needle bars 24 of the cylinder 10, the needles in each pair of such needle slots and grooves comprising a pair of needles indicated at 32 and 34. These needles, of the customary offset shape for this type of machine, are of similar formation with the exception that the shanks of the needles 32 are longer than the shanks of needles 34, the former being re ferred to as the long needles while the latter are referred to as the short needles. The needles 32 and 34 are intended to reciprocate to and between their latch clearing and stitch forming positions and, to this end, their shanks are provided with inwardly extending butts 36 and 38, respectively, which are engaged in vertically spaced, horizontally extending cam tracks 40 and 42, respectively, whereby the cam tracks operating upon the needle butts will so reciprocate the needles. The cam track 40 is formed between the lobes of the pull down cam ring 44 and the lobes of the raise cam ring 44a which together form the lower set of cams acting upon the butts 36 of the long needles 32. The cam track 42 is formed between the lobes of the pull down cam ring 46 and the lobes of the raise cam rinb 46a which together form the upper set of cams acting upon the butts 38 of the short needles 34. The cam tracks 40 and 42 are of similar configuration and the cam rings forming the two cam sets are suitably secured to the outer face of a hollow cylindrical cam core 48 which rotates about the post 14 positioned therein, the core being suitably secured to the member 50 which is rotated by suitable means (not shown) forming part of the machine. It should be noted, as appears in FIG. 1 and as shown schematically in FIG. 7, that the upper and lower cam sets have been positioned in such relatively angularly displaced relation on the cam core that the short needles 34 and the long needles 32 have their butts 38 and 36, respectively, on the tops of their raise cam lobes in the upper and lower cam tracks 42 and 40, respectively, at the same time. The number of degrees in the angular displacement between the two cam sets is indicated by the distance C, FIG. 7, between like portions of the two cam sets.

The number of degrees C in the circumferential displacement of the two cam sets is substantially equal to the number of degrees A between each pair of needle slots as well as between each pair of the needles 32 and 34 therein so that rotation of the cam sets relative to the needle cylinder and stem will cause the reciprocation of the needles to be of such order that, as shown in FIG. 7, each pair of needles 32 and 34 will rise and descend in unison with their needle hooks 32 and 34 remaining at a common level at all times during their movements to and between stitch forming and latch clearing positions. As the needles are so operated in pairs at the four feeds of the machine, they knit a tubular fabric 11 of yarns Y, two of which are shown in FIG. 1, around a flexible hose 13 as the latter is being drawn upwardly through the post 14 and the stem 12. The yarns Y are fed to the needles through suitable circumferentially spaced apertures formed in a surrounding outer depending ring 15 of a rotary head 17 of the machine. The fabric, as it comes from the needles, passes under an interiorly disposed depending ring 19 of the rotary head 17 and is drawn upwardly with and upon the upwardly moving flexible hose 13.

The operation of each pair of spaced needles 32 and 34 is schematically shown in FIGS. 9 and 10 wherein the pair of needles 32, 34 moving in unison, knits single spread stitches in a single wale, the provision of a common forecut 30 for the pair of needles permitting the formation of the single stitches on the pair of spaced needles. It will be noted that in each forecut 30 the material of the stem 12 has been removed from between each pair of the upper slots 26 and 28. See FIGS. 3 and 5. In FIG. 9 there is a loop ofa previously formed single stitch S in latch cleared position on the shanks of the common level raised needles 32, 34 with a yarn Y in their opened hooks 32', 34'. In FIG. 10, after the needles have moved down to common level stitch forming postion, a stitch S has been drawn through the cast off loop of the stitch S. The resultant fabric of the stitches S, as made upon all of the needles of the present machine, appears as in FIG. 8 upon the outer face of the hose 13.

It will be understood that there is no pinching or cutting of the yarns of the spread stitches formed upon the pairs of spaced needles because the latter, being conventional, are of conventional size, because they are spaced in individual spread needle slots, and because the needles of each pair thereof are moving in unison and at a common level at all times. It will also be understood that the present needle cylinder 10 and stem 12 are provided with a series of uniformly spaced pairs of normal width upper slots 26, 28 rather than with a series of uniformly spaced extra wide slots, and that, by the provision of the common forecut for each pair of the slots (30), each pair of needles forms single stitches.

For a given diameter of hose to be reinforced, the number of pairs of needle slots, and needles, as well as the angular spacing between each pair for the slots and between the displaced cam sets is so chosen that the resultantly formed stitches will have the desired size and space, previously set forth, and accordingly these factors may vary for different sizes of hose.

While the present machine has been shown as having four feeds, it will be understood that the present invention is not limited by the number of feeds on the machine. Also, the invention is not limited to a stationary cylinder type of machine nor to the direction of rotation of the machine. Additionally, the present principle of single spread stitch formation upon pairs of spaced needles is not limited to the formation of reinforce fab ric for flexible hose and is applicable generally to all type of knit fabrics.

In FIGS. 6 and 11, I show a prior art type of needle stem which employs a plurality of pairs of needle upper slots 54, 56. The needle upper slots 54, 56 are defined from each other by a portion 58 of the needle stem 52 in conventional manner. It will be noted that no undercut portion 30 is employed. In all such prior art designs, the offset needles 32, 34 were individually operated by cam tracks (not illustrated) in a manner to function sequentially. Simultaneously functioning needles as in the present invention could not be achieved in prior art devices inasmuch as the intervening portion 58 of the needle stem would interfere with stitch formation. As best seen in FIG. 11, the portion 58 would intercept the yarn Y if the needles 32, 34 were operated simultaneously, to thereby render the device completely inoperative. Gnly by employing the forecut 30 (FIG. 3) as herein taught by applicants can an operative device employing conventional needles be demonstrated.

Although we have described the present invention with reference to the particular embodiments herein set forth, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction may be resorted to without departing from the spirit and scope of the invention. Thus, the scope of the invention should not be limited by the foregoing specification, but rather only by the scope of the claims appended hereto.

We claim:

1. In a circular knitting machine having at least one yarn feed and including a needle cylinder, a pair of spaced lower slots in said cylinder, a pair of first and second latch needles individually disposed each in one of said lower slots, each of said needles being lengthwise movable in its slot to and between its latchclearing and cast-off positions, the combination'of A. actuating means for moving the pair of needles in unison between their latch-clearing and cast-off positions,

i. said actuating means including a pair of cams,

ii. one said cam actuating said first latch needle and the other said cam actuating the second latch needle,

B. a needle stem positioned above the needle cylinder and terminating upwardly in an upper edge portion,

i. said needlestem including a pair of spaced upper slots,

ii. each said upper slot being in vertical alignment above one said lower slot,

iii. each said upper slot being defined from a base and having sidewalls extending outwardly from the base,

a. the said needle stem having an outer periphery and the slot sidewalls extending outwardly from the base to the outer periphery,

C. spacer means separating the said spaced slots to knit said yarn feed into stitches, the width of which is a function of the course-wise distance between the first and second latch needles,

i. said spacer means separating the pair of upper slots at distance sufficient to accommodate the width of at least three conventional latch needles, and D. an undercut portion fabricated in said needle stem at its upper portion,

i. said undercut portion extending laterally between the pair of upper slots to provide a forecut common to the pair of slots and within which the stitches formed by the needles which are disposed in the slots may extend,

ii. said undercut portion extending downwardly within the upper edge portion a distance at least sufficient to correspond to the length of travel of the needles between their latch clearing and castoff positions and within which the stitches formed by the needles which are disposed in the upper slots may extend.

2. The invention of claim 1 wherein the undercut portion extends inwardly from the periphery of the needle stem to a depth at least equal to the depth of the base of the upper slots.

3. The invention of claim 2 wherein the upper slots upwardly terminate at the undercut portion and below the upper edge portion of the needle stem.

4. The invention of claim 3 wherein the undercut portion extends in width laterally beyond the upper slots outwardly of their non-adjacent sides to provide a forecut common to the pair of upper slots. 

1. In a circular knitting machine having at least one yarn feed and including a needle cylinder, a pair of spaced lower slots in said cylinder, a pair of first and second latch needles individually disposed each in one of said lower slots, each of said needles being lengthwise movable in its slot to and between its latch-clearing and cast-off positions, the combination of A. actuating means for moving the pair of needles in unison between their latch-clearing and cast-off positions, i. said actuating means including a pair of cams, ii. one said cam actuating said first latch needle and the other said cam actuating the second latch needle, B. a needle stem positioned above the needle cylinder and terminating upwardly in an upper edge portion, i. said needle stem including a pair of spaced upper slots, ii. each said upper slot being in vertical alignment above one said lower slot, iii. each said upper slot being defined from a base and having sidewalls extending outwardly from the base, a. the said needle stem having an outer periphery and the slot sidewalls extending outwardly from the base to the outer periphery, C. spacer means separating the said spaced slots to knit said yarn feed into stitches, the width of which is a function of the course-wise distance between the first and second latch needles, i. said spacer means separating the pair of upper slots a distance sufficient to accommodate the width of at least three conventional latch needles, and D. an undercut portion fabricated in said needle stem at its upper portion, i. said undercut portion extending laterally between the pair of upper slots to provide a forecut common to the pair of slots and within which the stitches formed by the needles which are disposed in the slots may extend, ii. said undercut portion extending downwardly within the upper edge portion a distance at least sufficient to correspond to the length of travel of the needles between their latch clearing and cast-off positions and within which the stitches formed by the needles which are disposed in the upper slots may extend.
 2. The invention of claim 1 wherein the undercut portion extends inwardly from the periphery of the needle stem to a depth at least equal to the depth of the base of the upper slots.
 3. The invention of claim 2 wherein the upper slots upwardly terminate at the undercut portion and below the upper edge portion of the needle stem.
 4. The invention of claim 3 wherein the undercut portion extends in width laterally beyond the upper slots outwardly of their non-adjacent sides to provide a forecut common to the pair of upper slots. 